Stumped

[jusenough]

30hp 1989 Evinrude. Symptom - Starts and idles.Initally runs to WOT and sounds fine.After warming I have a miss at idle and then it cycles raipdly on opening up the throttle.Tried spraying WD40 straight in the carb while it's cycling. No effect.tried squeezing the ball. No effect. After warm the miss at idle gets worse.Will be idling nicely and then suddenly backfire and stop. I suspect the power pack. It is new however as are the charge coil and stator and ignition coils and plug wires and plugs.Ignition advance works smoothly. Previously I only had fire on the bottom cyl. and did not have this problem. I have only had this problem since I replaced the power pack.I have gone back over it looking for pinched wires (none).Entire fuel system is also new.Suggestions??

 

[The Marine Doctor]

Re: Stumped

Try opening the low speed jet 1/8 of a turn counterclockwise.<br /><br />TMD

 

[jusenough]

Re: Stumped

I allready tried messing with the low speed jet. I changes my Idle but has no effect on the problem. I also put my finger over the needle/ little tube the needle sets in, to check for a air leak. No effect. My compression is 122 on both cold and 110 on both hot. I was thinking that if I had a fuel problem It would effect the run when I sprayed it while cycling ( should take off) and this has no effect.

 

[Joe Reeves]

Re: Stumped

If you're going to spray anything into the carburetor throat, spray a fuel/oil premix solution in there, not WD40.<br /><br />You say in effect that you've replaced everything that could be replaced, but your explanation has me thinking that possibly you've overlooked something in the carburetor.<br /><br />Remove and double check the carburetor, especially the brass high speed jet (may be clogged somewhat) that's located in the bottom center of the float chamber, the idle air bleed jet (ID may be slightly too large) that's located at the top front of the carburetor upper body, and last but not least, the small brass tube that leads from the bottom portion of the carburetor upper body to the extreme top of the carburetor (slow speed fuel passageway).<br /><br />Note that you can check the top idle air bleed jet for being too large by simply having the engine running, then gently insert a pointed toothpick into the jet to reduce the ID opening. If the engine smooths out, the jet is too large. Don't jam the toothpick in there, just take up some of the ID with it.<br /><br />Any clogged conditions or a wrong size idle air bleed jet would cause the engine to run lean, resulting in a sneezing condition firing out the carb throat (sounds like a mild backfire).<br /><br />Also, try the slow speed adjustable setting (needle valve at top starboard of carb) as follows:<br /><br />(Carburetor Adjustment - Single S/S Adjustable Needle Valve)<br /><br />Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.<br /><br />Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.<br /> <br />Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting. <br /><br />When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[jusenough]

Re: Stumped

Joe, I had initally suspected a fuel problem even though I had allready done the carb and a pump rebuild. This motor sat for years and I had not replaced the lines,I thought maybe I pulled some trash out of the old lines, so I pulled the carb., replaced all fuel lines, replaced the fuel pump and cleaned all parts you mention assuring that all were clean as a pin.I even polished the larger orfice inside with a wooden match stick Prior to doing this I tried several float settings and then finally putting the old float back in so I check it's set agianst the set on mine.The old float was set at level minus 1/4" with 3/4" drop.I tried running it and no change so I bought carb kit #2, completly went over the carb. and set the new float at level minus just a hair maybe 1/16" with 3/4" drop. This also didn,t make any differance in the way it ran. I can't figure out why it will initally run ok and then mess up once it's run for a minute. I,ve got a long fuel line maybe 12' as the tank sets up front. This line is the only one I did not replace. The boat is light in the front and the original owner had done this. The line runs from my new tank to a regular spin on water/ gas seperator filter( also by the previous owner, I simply changed the filter) to the new squeeze ball. I flushed the old line and it is in front of both the seperator filter and the pump screen so I don't think dirt is a issue. Besides, pumping the ball while the engine cycles has no effect. I,ll try shooting premix in the carb while its cycling and see what that does. The thing acts like the timing is not advancing or it is only getting fuel / spark in two second cycles on and off. With the throttle at 1/2 it will buck like a bronco.

 

[jusenough]

Re: Stumped

I tried Moving my tank back next to the motor. No change. I tried premix straight into the carb while it was cycling. No change. I did notice that since I have added the new charging coil and stator it seems to take two minutes as opposed to one to act up. Also I would describe the backfire at idle more like a sneeze, out the upper exhaust. I swear I was sold a bad coil but dont know how to check it.

 

[denniz]

Re: Stumped

carb linkage out of sync.

 

[Joe Reeves]

Re: Stumped

JusEnough... I've read over your recent post and see that you've just about covered all bases. Strange that the sneezing effect gets worse when the engine warms up. Usually the exact opposite is true.<br /><br />As "Rod Knocking" has mentioned, the carb linkage may be out of synchronization, but if so, that sneezing should be a constant steady problem regardless of whether the engine's cold or warm. However, check to see that the throttle starts to open exactly when the scribe mark on the cam lines up with dead center of the carburetor roller, not before.<br /><br />A problem such as what you've encountered happened to various older V/6 engines (1980s somewhere) which was due to a slightly warped intake manifold. The cure was to double up on the intake manifold gasket. Might be worth a try to double up on the carb to intake manifold gasket along with the manifold to crankcase gasket.<br /><br />I assume that you're using Champion QL77JC4 plugs. If not, do so. I think the manual states to set the gap at .030 but if so, try a gap setting of .040 . The .040 setting has been used from 1973 to right around 1990 and works quite well. I don't know why OMC narrowed the gap but I do know that many engines run much better at idle with the .040 setting.<br /><br />Your float level explanation sounds right if you're holding the carburetor upright. However, it's easier to set the float as follows:<br /><br />(Carburetor Float Setting)<br /> <br />With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (off level) than the other end. And when viewed from the end, make sure it is not cocked.<br /><br />The wording you use in your post (Bucking) might be misleading somewhat. That might tend to indicate that the engine was jumping out of and back into gear when the engine is running, in gear, at a high rpm. But I am assuming that you're still speaking of a rpm near idle, in neutral. Keep us informed.

 

[nburford]

Re: Stumped

I'm sure most here forgot more than I would ever know about motors, but I had a similar problem that wound up being a crack in the fuel filter casting. You could try running out of a can (safety first) and bypass the hose and filter, that would be simple and would eliminate them as possible causes.<br />Good luck.<br />-Nick

 

[jusenough]

Re: Stumped

I appreciate the imput guys. I had bypassed the fuel filter last night when I tried the short fuel hose.I agree that the sync would create such a problem but can't figure out why it is fine prior to warming. I did notice that in order to get the cam roller to line up between the marks I had to go all the way in with the nylon adjustment screw which I thought was odd.

 

[Hooty]

Re: Stumped

I'm thinkin' like Jusenough. It sounds "ignition" to me. Since it does it deal after warm-up, try warming the powerpack with a hair drier (J.B.'s trick) before starting and see if that makes a difference in the way it starts and runs when everything else is cold, or just try another p/p.<br /><br />c/6<br /><br />Hooty

 

[jusenough]

Re: Stumped

Hooty- My PP is under the flywheel so Im not so sure how well the hair dryer would work. I considered another PP but at $115 It is my last resort. I asked the parts desk guys if anyone had ever complained that they had been sold a bad PP. They said that this has never happened. I find that hard to belive but on the other hand they have been a real helpfull bunch.Much more likely this non-mechanic has overlooked something obvious or done something stupid. The power pack had a male needle type connector that went on the black yellow ignition wire. It was easyer for me to simply use the old end so I cut it off the old PP and used it on the new. I need to redo that connector allthough I doubt thats the problem. I can't imagine what the problem may be with a totally new fuel and ignition systems and I am now grabbing at straws.

 

[Hooty]

Re: Stumped

I'm not familiar with that year 30hp engine but usually grounding the black and yellow wire kills the engine. Could it be floppin' around somewhere and intermittently grounding?<br /><br />c/6<br /><br />Hooty

 

[jusenough]

Re: Stumped

Hootey- I allready checked for that.I went over the sync again and got a pretty idle allthough I did get a spit and shut off once.Right where the carb should start to crack I got the same ole thing. I took the motor to a friend who is a mechanic. He tells me that I didn't have a hot enough spark on #1 despite a completly new system. He sanded the inside of the flywheel and the pickup on the PP. He now has the opposite that I had. He got it to take it and run at WOT hot but now has an idle that cuts in and out.He says he backed the air orfice out where it is not supposed to be and other than that he dosen,t know what he did to change it. He thinks it is my carb but I am not so sure. This is driving me nuts.

 

[Solittle]

Re: Stumped

http://www.outboardrepairs.com/carburetors/

 

[jusenough]

Re: Stumped

OK- I think I have come up with the answer. 1989 & 90 30 thru 40 hp have a tempature sensor hooked to the power pack. This is designated with a S in between the U & L on the power pack or CD ignition model #. It stands for speed limiting overheat warning (S.L.O.W.)I have a deffective sensor. I think I also have a deffective thermostat since I noticed that it gave me steam in leu of water out the water tube when warm for 30 seconds then water agian. This exsplains why it only does it's trick when warm. The other night I put it in the river and I initally got to WOT but after 30 seconds it slam shut down and then started it's cycling trick agian. I was able to run smooth at 1/4 throttle and kept on going to middle river where I shut it off and had a couple cold ones while drifting and watching the sun set. ( I had my buddy follow me just in case). Afterwards I started it up and ran it up to WOT. The thing screamed and I felt like I had about 2 inches of boat in the water. 30 seconds latter, same thing and I putted back to the dock SLOW. Conclusion is that I need to replace both the thermostat and the sensor.